reifydb-routine 0.4.5

Built-in routines (functions and procedures) for ReifyDB
Documentation 
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// SPDX-License-Identifier: Apache-2.0
// Copyright (c) 2025 ReifyDB

use reifydb_core::value::column::data::ColumnData;
use reifydb_type::value::{container::utf8::Utf8Container, r#type::Type};

use crate::function::{
	ScalarFunction, ScalarFunctionContext,
	error::{ScalarFunctionError, ScalarFunctionResult},
	propagate_options,
};

pub struct TextReverse;

impl TextReverse {
	pub fn new() -> Self {
		Self
	}
}

impl ScalarFunction for TextReverse {
	fn scalar(&self, ctx: ScalarFunctionContext) -> ScalarFunctionResult<ColumnData> {
		if let Some(result) = propagate_options(self, &ctx) {
			return result;
		}

		let columns = ctx.columns;
		let row_count = ctx.row_count;

		if columns.len() != 1 {
			return Err(ScalarFunctionError::ArityMismatch {
				function: ctx.fragment.clone(),
				expected: 1,
				actual: columns.len(),
			});
		}

		let column = columns.get(0).unwrap();

		match &column.data() {
			ColumnData::Utf8 {
				container,
				max_bytes,
			} => {
				let mut result_data = Vec::with_capacity(row_count);

				for i in 0..row_count {
					if container.is_defined(i) {
						let reversed: String = container[i].chars().rev().collect();
						result_data.push(reversed);
					} else {
						result_data.push(String::new());
					}
				}

				Ok(ColumnData::Utf8 {
					container: Utf8Container::new(result_data),
					max_bytes: *max_bytes,
				})
			}
			other => Err(ScalarFunctionError::InvalidArgumentType {
				function: ctx.fragment.clone(),
				argument_index: 0,
				expected: vec![Type::Utf8],
				actual: other.get_type(),
			}),
		}
	}

	fn return_type(&self, _input_types: &[Type]) -> Type {
		Type::Utf8
	}
}